Telecommunication systems using light propagating in different waveguides expand more and more today. There is a large interest in extending the optical networks even up to private homes and local business estates, the so called local access network which is also called "Fibre To (In/From) the Home", "Fibre To (In/from) the Customer (Business)", etc. Also, there is a large interest in extending the use of optical networks in LANs, i.e. local area networks, used for interconnecting computers in a business estate and furthermore for communication inside computer equipment and for communication between computers and peripheral devices such as printers etc. In order to achieve this expansion, the costs of the components of the optical networks of course have to be reduced as much as possible. Very important costs are related to producing the optical transmitter and receiver modules including lasers, LEDs, etc. and other active or passive is devices.
In optical transmitter and receiver modules and other optical products which have integrated waveguides for light there is a need for mirrors which can reflect light or generally make a abrupt change of the direction of light propagated in the optical waveguides such as to deflect the light out of a waveguide to some receiver. Mirrors which can generally be formed by end surfaces of optical waveguides can be produced using different methods. Mirrors in the waveguide plane achieving a reflection at a surface to air has been disclosed by Honeywell, for example for creating sharp 90.degree. bends in a waveguide, and mirrors for deflecting light out of a waveguide plane have been disclosed by Dupont and IBM, see for example Lawrence A. Hornack, editor "Polymers for lightwave in integrated optics", Marcel Decker K. K., New York, 1992, Chapter 9 by B. Booth, Dupont. In the company Ericsson, he department MIRC has in cooperation with the Institute for Optical Research disclosed mirrors in waveguides for defecting out of a waveguide plane produced by means of an UV-excimer laser, see Gunnar Bostrom, "Waveguide grating couplers", graduate report at the Royal Institute of Technology, Stockholm, Trita. Phys. 2138, Sep. 15, 1994.
In U.S. Pat. No. 5,327,415 a method of producing a reflector for a laser in a semiconductor material is described, see FIGS. 2a-2c. A metal mask having 28, 34 defines the opening of the reflector at the surface of the material.